Methods of providing reclaimed rubber



p 1957 c. H. PETERSON 2,304,651

METHODS OF PROVIDING RECLAIMED RUBBER Filed Nov. 9, 1953 2 Sheets-Sheetl M/mva .90 .32 12 I I IOLAST/C/Z/NG flTPUD/NG SHIPPING Thqll.

BY ATTOl I Filed Nov. 9, 1953 Sept. 3, 1957' c. H. PETERSON METHODS OFPROVIDING RECLAIMEID RUBBER INVENTORZ ATTORNE United States Patent Ofiiice Patented Sept. 3, 1957 IVIETHODS OF PROVIDING RECLAIMED RUBBERChester H. Peterson, Eggertsville, N. Y., assignor to U. S. RubberReclaiming Co. Inc., Bulfalo, N. Y.

Application November 9, 1953, Serial No. 390,907

Claims. (CI. 18-48) This invention relates to methods for providingreclaimed rubber. In particular, it is directed to economical andeffective methods adapted for the production of an improved reclaimedrubber product. To this end, the invention contemplates the provision ofa method wherein the reclaim is extruded at a relatively low temperatureand under relatively low pressure after the completion of the reclaimingoperation. This is both more effective and more economical than arefining operation (e. g., by forming into a thin sheet between rolls)and sometimes than several sheeting operations; but it can be combinedwith a sheeting operation to provide an especially useful product.

The invention accordingly comprises the several steps and the relationand order of one or more of such steps with respect to each of theothers, as exemplified in the following detailed disclosure, and thescope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

' Figure 1 is a diagrammatic showing of one form of the invention;

Fig. 2 is a vertical sectional view of the discharge end of theplasticator;

Fig. 3 is a front view thereof; and

Fig. 4 is a diagrammatic showing of a modification.

In the embodiment of the invention exemplified in Fig. l, vulcanizedrubber crumb is mixed with reclaiming agents at and passed into andsubjected to a plasticizing reclaiming operation as by being passed thrua screw plasticator at 12 where it is reclaimed. The plasticator may beone of the types exemplified in the Elgin et a1. Patent 2,653,348. Anoutlet head portion, as exemplified in Figs. 2 and 3 hereof, provides aclear, open 2 channel which is free of internal obstructions and whencethe reclaim will issue in strip (s1ab or sheet) form.

As exemplified, the head comprises a half-inch plate 15 which is reducedto A" at aninner circular portion 18 which has a diameter of 2%" and thecentral portion of which is formedwith a tapering portion ending in anopening 19 which is 0.65" in height and 1.9" in horizontal extent.Beyond this opening is a nose 20 which in the present instance is 4" inlength and provides a channel 21 which conforms to the opening 19 andthen tapers in the thickness dimension to 0.05" and expands in width to2.5 to provide an opening 22. The nose 20 is held in place bycooperating shoulders 23 and 24 on the nose and on a plate 25 which liesagainst and is secured to the plate 15. Pressures of over 800 p. s. i.,and desirably 900 to 2500 p. s. i., are developed therein, andtemperatures from 325 F. to 500 F.

From the opening 22, the reclaimed material passes, as on a conveyor 27,thru a zone 28 wherein it is cooled, as by the surrounding atmosphere,and then is subjected to an extrusion step, as by being passed thru anextruder at 30, whence it issues in condition to be stored or to beshipped as indicated at 32. The extruder in the present instance is ascrew of the extruder type shown on page 261 of Extrusion of Plastics,Rubber, and Metals, by Simmons, Weith and Schack (Reinhold), but iswatercooled rather than heated. Temperatures in the extruder run about250 F. and may run from to 275 F.

The product has higher tensile strength and 300% modulus, and a higherMooney than reclaims subjected to the usual refining operations, as wellas improved working and handling properties. A stock treated as abovehad a tensile of 1665 lbs. as compared with 1560 lbs. for a similarstock treated similarly except that, after reclaiming, it was sheetedinstead of extruded; a 300% modulus of 755 as compared with 610, and aMooney (ML/2l2/1-5) of thirty as compared with twenty-five.

An average of random runs of truck and bus tire reclaim showed adecrease of twelve Mooney units (ML/ 212/ 1-5 during extruding, whereasa greater average decrease-fifteen Mooney unitstook place duringrefining in random runs of truck and bus tire reclaim. The averagedecrease during extruding in random runs of passenger tire reclaim wassix Mooney units as against sixteen Mooney units during refining inrandom runs.

It is possible, moreover, in accordance with the present invention, toobtain the advantages of the extrusion operation by subjecting theretosheeted stock. As shown in Fig. 4, reclaim from the plasticating step 12may be subjected to a sheeting step as by a sheeter at 40 prior to theextrusion step at 30 and the shipping step at 32.

While there are given above certain specific examples of this inventionand its application in practical use and also certain modifications andalternatives, it should be understood that these are not intended to beexhaustive or to be limiting of the invention. On the contrary, theseillustrations and the explanations herein are given in order to acquaintothers skilled in the art with this invention and the principles thereofand a suitable manner of its application in practical use, so thatothers skilled in the art may be enabled to modify the invention and toadapt it and apply it in numerous forms, each as may be bested suited tothe requirement of a particular use.

I claim:

1. The process of providing reclaimed rubber of improved tensilestrength, viscosity, and modulus, which comprises working comminutedvulcanized rubber while progressively forcing it forward thru anelongated chamber and out of a restricted orifice in a hot plasticcondition and in a continuous mass, conducting the mass thru theatmosphere to cool the mass and delivering it to a second elongatedchamber, forcing it thru the second chamber while working it, andextruding it from the second chamber thru a restricted orifice.

2. A process as in claim 1 wherein the rubber is extruded from bothchambers in continuous strip form.

3. A process as in claim 1 wherein the rubber is conducted upwardly fromthe first-mentioned chamber to said second chamber on a conveyor.

4. A process as in claim 1 wherein the rubber is con ducted over andbetween rolls from the first-mentioned chamber to said second chamber.

5. A process as in claim 1 wherein the rubber is forced thru saidchambers by screws and wherein the pressure generated in thefirst-mentioned chamber is over 800 pounds per square inch.

References Cited in the file of this patent UNITED STATES PATENTS1,680,171 Hollenbeck Aug. 7, 1928 (Other references on following page) 34 UNITED STATES PATENTS 2,595,210 Clinefelter Apr. 29, 1952 1,908,564Slusser May 9, 1933 25151205 Gray 1952 2,286,966 Johnson June 16, 1942OTHER REFERENCES 2,471,392' Campbell May 24, 1944 5 How to SlashDevulcamzatlon Tlme, Chem1ca1 En- 2371722 Wanderer 1945 gineering, pp.192 and 194, July 1951.

2,499,913 Gordon Mar. 7, 1950 4 vii

